A Study of charged D* production in e+ e- annihilation at an average center-of-mass energy of 58-GeV

The VENUS collaboration Hinode, F. ; Abe, K. ; Amako, K. ; et al.
Phys.Lett.B 313 (1993) 245-252, 1993.
Inspire Record 353854 DOI 10.17182/hepdata.28865

We have studied the production of charged D ∗ mesons in e + e − annihilation at an average center-of-mass energy of 58.0 GeV. Charged D ∗ mesons were identified using two independent methods; the mass-difference method and the detection of the low transverse-momentum pion. The forward-backward asymmetry of the charm quark production was measured to be A c = −0.61±0.13(stat.)±0.08(syst.). The cross section of inclusive D ∗ production was found to be σ(e + e − →D ∗ ± +X) = 24.5 ± 5.3 ( stat. )±3.0( syst. ) pb. If we assume the standard model prediction for the charm quark production, we obtain the branching ratio for the charm quark to produce a charged D ∗ meson to be Br (c→D ∗+ + X) = (22±5( stat. )±3( syst. ))% .

1 data table match query

Forward-backward asymmetry of charm quarks at the lowest order.


Study of the $e^+ e^-\to\mu^+ \mu^- \gamma$ reaction at center-of-mass energies between 54 and 64 GeV

The VENUS collaboration Yonezawa, Y. ; Abe, K. ; Amako, K. ; et al.
Phys.Lett.B 264 (1991) 212-218, 1991.
Inspire Record 1389624 DOI 10.17182/hepdata.29359

The cross section and forward-backward muon charge asymmetry for the e + e − → μ + μ − γ reaction were measured to be σ =2.82±0.35 pb and A =−0.34±0.10 with the VENUS detector at TRISTAN at 〈√ s 〉=59.2GeV for an integrated luminosity of 53.5 pb −1 . The measured cross section agrees with the theoretical prediction. The asymmetry result is consistent with the electroweak prediction but not with the QED prediction at the level of 2 σ .

1 data table match query

No description provided.


Measurement of the forward - backward asymmetry in e+ e- ---> b anti-b and the b quark branching ratio to muons at TRISTAN using neural networks

The AMY collaboration Ueno, K. ; Kanda, S. ; Olsen, S.L. ; et al.
Phys.Lett.B 381 (1996) 365-371, 1996.
Inspire Record 418709 DOI 10.17182/hepdata.38513

The forward-backward asymmetry in e + e − → b b at s = 57.9 GeV and the b-quark branching ratio to muons have been measured using neural networks. Unlike previous methods for measuring the b b forward-backward asymmetry where the estimated background from c -quark decays and other sources are subtracted, here events are categorized as either b b or non- b b events by neural networks based on event-by-event characteristics. The determined asymmetry is −0.429 ± 0.044 (stat) ± 0.047 (sys) and is consistent with the prediction of the standard model. The measured B B mixing parameter is 0.136 ± 0.037 (stat) ± 0.040 (sys) ± 0.002 (model) and the measured b-quark branching ratio to muons is 0.122 ± 0.006 (stat) ± 0.007 (sys).

1 data table match query

A Study of the charm and bottom quark production in e+ e- annihilation at s**(1/2) = 58-GeV using prompt electrons

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 313 (1993) 288-298, 1993.
Inspire Record 355172 DOI 10.17182/hepdata.28868

We have studied c (charm) and b (bottom) quark production at the TRISTAN energy region by tagging prompt electrons from the semileptonic decays. Electrons were identified over a wide momentum range between 1 and 29 GeV/ c by a transition-radiation-detector in addition to a lead-glass calorimeter. The production cross sections of c and b quarks and the mean values of the fragmentation functions for c and b quarks were obtained as σ c = 55.9±8.8(stat.)±7.9(syst.) pb, σ b = 13.1±2.9(stat.)±1.0(syst.) pb, 〈 x c 〉 = 0.44±0.08(stat.)±0.04(syst.) and 〈 x b 〉 = 0.72±0.12(stat.)±0.08(syst.), respectively. The forward-backward asymmetries of the c and b quarks were also measured to be −0.57±0.16(stat.)±0.06(syst.) and −0.64±0.26(stat.)± 0.07(syst.), respectively. Both the cross sections and the forward-backward asymmetries of the c and b quarks are consistent with the standard model.

2 data tables match query

No description provided.

No description provided.


Measurements of cross-section and asymmetry for e+ e- ---> b anti-b and heavy quark fragmentation at KEK TRISTAN

The AMY collaboration Liu, F. ; Chinitz, L.M. ; Abe, K. ; et al.
Phys.Rev.D 49 (1994) 4339-4347, 1994.
Inspire Record 381324 DOI 10.17182/hepdata.22547

Using 773 muons found in hadronic events from 142 pb−1 of data at a c.m. energy of 57.8 GeV, we extract the cross section and forward-backward charge asymmetry for the e+e−→bb¯ process, and the heavy quark fragmentation function parameters for the Peterson model. For the analysis of the e+e−→bb¯ process, we use a method in which the behavior of the c quark and lighter quarks is assumed, with only that of the b quark left indeterminate. The cross section and asymmetry for e+e−→bb¯ are found to be Rb = 0.57 ± 0.06(stat) ± 0.08(syst) and Ab = −0.59 ± 0.09 ± 0.09, respectively. They are consistent with the standard model predictions. For the study of the fragmentation function we use the variable 〈xE〉, the fraction of the beam energy carried by the heavy hadrons. We obtain 〈xE〉c=0.56−0.05−0.03+0.04+0.03 and 〈xE〉b=0.65−0.04−0.06+0.06+0.05, respectively. These are in good agreement with previously measured values.

1 data table match query

No description provided.


Charge Asymmetry of Hadron Jets and Limits on the Compositeness Scales in e$^{+} $e$^{-} \To $q$ \Bar{$q$}$ Reaction at $\Sqrt{$s$}=57$.6-{GeV}

The VENUS collaboration Abe, K. ; Amako, K. ; Arai, Y. ; et al.
Phys.Lett.B 232 (1989) 425-430, 1989.
Inspire Record 281245 DOI 10.17182/hepdata.29751

A charge asymmetry has been measured in hadron jets from e + e − annihilation at energies between 52 and 61.4 geV (〈√ s 〉=57.6 GeV). The measured asymmetry is A =11.4%±2.2%±2.1% and is consistent with the prediction of the standard model of the electroweak theory. By using the differential cross section, lower limits of the compositeness scale in eeqq contact interactions have been determined to be typically a few TeV at 95% CL.

1 data table match query

Data are fully corrected for detector effects, resolution and radiative effects.


Precise measurement of the e+ e- ---> mu+ mu- reaction at s**(1/2) = 57.77-GeV

The VENUS collaboration Miura, M. ; Odaka, S. ; Arima, T. ; et al.
Phys.Rev.D 57 (1998) 5345-5362, 1998.
Inspire Record 452097 DOI 10.17182/hepdata.27142

The reaction e+e−→μ+μ− has been measured at s=57.77GeV, based on 289.6±2.6 pb−1 data collected with the VENUS detector at TRISTAN. The production cross section is measured in bins of the production angle within an angular acceptance of |cosθ|<~0.75, according to a model-independent definition. The result is consistent with the prediction of the standard electroweak theory. Although a trend in measurements at lower energies that the total cross section tends to be smaller than the prediction remains, the discrepancy is not significant. The model-independent result is converted to the differential cross section in the effective-Born scheme by unfolding photon-radiation effects. This result can be extrapolated to quantities for the full solid angle as σtotEB=30.05±0.59 pb and AFBEB=−0.350±0.017, by imposing an ordinary assumption on the production-angle dependence. The converted results are used to set constraints on extensions of the standard theory. S-matrix parametrization, and possible contributions from contact interactions and heavy neutral-scalar exchanges are examined.

1 data table match query

Total cross section and forward backward asymmetry results in the effective-Born scheme.


A MEASUREMENT OF e+ e- ---> b anti-b FORWARD - BACKWARD CHARGE ASYMMETRY BETWEEN s**(1/2) = 52-GeV AND 57-GeV

The AMY collaboration Sagawa, H. ; Lim, J. ; Abe, K. ; et al.
Phys.Rev.Lett. 63 (1989) 2341, 1989.
Inspire Record 279824 DOI 10.17182/hepdata.19996

Using 123 multihadronic inclusive muon-production e+e− annihilation events at an average c.m. energy of 55.2 GeV, we extracted the forward-backward charge asymmetry of the e+e−→bb¯ process and the R ratio for bb¯ production. We used an analysis method in which the behavior of the c quark and lighter quarks is assumed, with only that of the b quark left indeterminate. The results, Ab=-0.72±0.28(stat)±0.13(syst) and Rb=0.57±0.16±0.10, are consistent with the standard model.

1 data table match query

Asymmetry in BOTTOM quark production.


Forward cross-sections for production of D+, D0, D/s, D*+ and Lambda/c in 250-GeV pi+-, K+-, and p nucleon interactions.

The E769 collaboration Alves, G.A. ; Amato, S. ; Anjos, J.C. ; et al.
Phys.Rev.Lett. 77 (1996) 2388-2391, 1996.
Inspire Record 418771 DOI 10.17182/hepdata.42294

We measure forward cross sections for production of D+, D0, Ds, D*+, and Λc in collisions of π±, K±, and p on a nuclear target. Production induced by different beam particles is found to be the same within statistics. Strange and baryonic final states are seen to contribute appreciably to the total charm cross section, which our measurements indicate is larger than but consistent with QCD predictions. The energy dependence mapped out by these and previous measurements is consistent with theory. Leading-particle asymmetry measurements for K and p-induced charm production are also presented.

1 data table match query

Leading particle asymmetries defined as (SIG(LEADING)- SIG(NONLEADING))/(SIG(LEADING)+SIG(NONLEADING)).


Precision study of the eta-3He system using the d+p->3He+eta reaction

Mersmann, T. ; Khoukaz, A. ; Buscher, M. ; et al.
Phys.Rev.Lett. 98 (2007) 242301, 2007.
Inspire Record 743387 DOI 10.17182/hepdata.31493

The differential and total cross sections for the d+p->3He+eta reaction have been measured in a high precision high statistics COSY-ANKE experiment near threshold using a continuous beam energy ramp up to an excess energy Q of 11.3 MeV with essentially 100% acceptance. The kinematics allowed the mean value of Q to be determined to about 9 keV. Evidence is found for the effects of higher partial waves for Q>4 MeV. The very rapid rise of the total cross section to its maximum value within 0.5 MeV of threshold implies a very large eta-3He scattering length and hence the presence of a quasi-bound state extremely close to threshold.

1 data table match query

Angular distribution asymmetry parameter defined as:. SIG(TOTAL)*(1+ASYM*COS(THETA(CM))/4*PI.